Grinding machine



June 7, 1932. K. F. GALLIMORE GRINDING MACHINE Original Filed July 221925 l0 Sheets-Sheet 1 frlIlIlliizil i Il ILitliJ.. 2

io sheets-sheet 2 Nmx `[une 7, 1932.

K. F. GALLIMORE GRINDING MACHINE Original Filed July 22 1925 June 7,1932. K. F. GALLIMORE:

GRINDING MACHINE Original Filed July 22, 1925 10 Sheets-Sheet 5 June 7,1932. K. F. GALLIMORE: 1,862,215

GRINDING MACHINE Original Filed July 22, 1925 l0 Sheets-Sheet 4 iL-CDH65 @l 69 il H62 l r'@ E3 fr, a f3 @Z @fr f/ T95' un ....4. ,.Hi

June 7,1932. K F, GALUMQRE 1,862,215

GRINDING MACHINE Original Filed July 22. 1925 l0 Sheets-Sheet 5 June 7,1932-' K. F. GALLlMoRE: 1,862,215

GRINDING MACHINE l Original Filed July 22 1925 l0 Sheefs-Sheet 6 June 7,1932. K. F.

GALLIMORE 1,862,215

GRINDING MACHINE Originall Filed July 22 1925 10 Sheets-Sheet* 7 June 7,1932.

K. F. GALLIMORE GRINDING MACHINE l0 Sheets-Sheet 8A Original Filed July22 l jaLt/v Ca/amara ,af/@lk v June 7, 1932. K. F. GALLIMORE GRINDINGMACHINE original Filed'July 22. 1925- l10 Sheets-Sheet 9 m, r I f A s.BMD Vm SN @NN um, A n N@ n 5w mw n H Lm s: Qn.

June 7, 1932. K. F. GALLlMoRE GRINDING MACHINE Original Filed July 221925 10 Sheets-Sheet 10 brought from a remote Patented June 7, 1932UNITED .STATES PATENT OFFICE KEITH F. GALLIMORE, 0F FOND DU LAC,WISCONSIN, ASSIGNOR, BY MESNE .ASSIGN- MENTS, T0 THE HEALD MACHINECOMPANY, OF WORCESTER, MASSACHUSETTS; A.

CORPORATION 0F MASSACHUSETTS 4GIRINDIN'G' MACHINE Application led July22, 1925, Serial No. 45,164. Renewed November 23, 1929.

AThe present invention relates to improvements in grinding machines, andhas .particular reference to automatic interna-l grinders in which thegrinding wheel is automatically inoperative position into an operativeposition relative tothework, is reciprocated in contact with the Work,and at the completion of the grinding operation is automaticallyreturned to its inoperative position.

The primary object of the invention is to provide a fixed Wheel truingdevice which will automatically dress the grinding Wheel at thecompletion of the rough grinding operation, i. e. a predetermined timeafter the beginning and before the completion of the grinding operation.

A more specific object is to provide in combination with a fixed wheeltruing device mounted on the headstock carriage for movement therewith,means for automatically effecting the temporary withdrawal of thelgrinding wheel from the work at a predetermined point in the grindingoperation, and means for automatically effecting a separation of thegrinding wheel and the finished surface of the work in a directionperpendicular to thelatter at the completion of the grinding operation,the first movement serving to carry the grinding wheel past the truingdevice to engage therewith, and the second movement serving to permitthe grinding wheel to he drawn into its inoperative position Withoutagain engaging the finished surface of the work or the truing device. y

Further `objects and advantages will become apparent as the descriptionproceeds.

In the accompanying drawings, Figure 1 is a front view of a grindingmachine embodying the features of my invention.

Fig. 2 is a plan view of the machine.

Fig. 2a is a fragmentary sectional view of the dressing tool support.

Fig. 3 is a vertical sectional view of the headstock carriage takenalong line 3 3 of Fig. 2.

Fig. 4 is a sectional view of the gage controlled switch taken alongline 4-4 of Fig. 3.

Fig. 5 is a sectional view of said switch taken along line 5-5 of Fig.3.

Fig. 6 is a vertical sectional view -of the feeding mechanism takenalong line 6-6 of Fig. 2. i i;

Fig. 7 is a fragmentary vertical sectional view taken along line 7-7 ofFigure 1.

Fig. 8 is an enlarged fragmentary view of the front of the machine, saidview showing the main control valve and the reversing switch in section,and the control dogs and levers.

Fig. 9 is a sectional view lof the valve taken along line 9 9 of Fig. 8.

Fig. 10 is a perspective view of one of the reversing dogs. i d Fig. 11is a perspective view of another Fig. 12 is a vertical sectional viewtaken substantially along line 12-12 of Fig. 1.

Fig. 13 is a fragmentary sectional view taken substantially along line13-13 of Fig. 12.

Fig. 14 is a sectional view taken alongline 14-14 of Fig. 12.

Fig. 15 is a diagrammatic representation of the hydraulic operatingsystem and of the electric circuits for operatin and controlling theoperation of the mac ine carriages.

Fig. 16 is a sectional view taken substantially in the plane of line16--16 of Fig. 1.

While the invention is susceptible of varions modifications andalternative constructions and adaptations, I have shown'in the drawin sand will herein describe in detail the pre erred embodiment, but it isto be understood that I do not thereby intend to limit the invention tothe specific form disclosed, but aim in the appended claims to cover allmodifications and alternative constructions and adaptations fallingwithin the spirit and scope of the invention.

Referring now more particularly to .the

specific construction of the exemplary em-` bodiment of the invention,the machine comprises a hollow base casting 16 having an internaltransverse wall 17 which separates the base into a long bed on which agrinding spindle carriage 18 is mounted and a side portion on which aheadstock carriage 19 is mounted. Between the wall 17 and anothertransverse Wall 20 is a chamber adapted to tween the grinding wheel andthe work, and

to direct pressure fluid to a hydraulic motor on the grindingspindlecarriage to cause the latter to move from an inoperative positionremote from the headstock carriage into operative position in which thegrinding wheel and' the work are positioned in operative relation, toreciprocate the grinding spindle carriage in its operative position, totemporarily move said carriage partly toward its inoperative positionand immediately return the same to its operative position thereby effthe invention any suitable power means may fecting a temporarywithdrawal of the grind' ing wheel from the work, and when the grindingoperation is completed to return the grinding spindle carriage to itsinoperative position. The feeding mechanism initially provides a coarsecross feed for the roughing cuts, and finally provides a line cross feedfor the finishing cuts. A gage is provided which coacts with. the workand which is effectual to institute the reduction in the cross feed andthe temporary` and permanent withdrawals of the grinding Wheel from thework. A fixed wheel dressing device is mounted on the headstock carriageto dress the grinding Wheel as it moves. past on its temporarywithdrawal movement from the work. Hydraulic means having a supplementalvalve under the controlof the. gage serves to effect a separation of thegrinding Wheel and the work in a direction perpendicular to the surfaceof the latter when the grinding operation is completed and ybefore theWheel 4is withdrawn beyond the end of the ground surface, therebypreventing the grinding wheel from engaging the end of the round surfaceand the dressing tool on its nal Withdrawal.

While hydraulic means is employed to acl tuate the carriages and Whileeach of thecarriages is given certain specific movements, it is to beunderstood that for the purposes of be employed, and the machinemovements broadly outlined may be given to either of the carriages sincethe movements between the carriages are required only to be relative.

The grndz'ng spindle carriage The inding spindle carriage 18 (see Figs.

1 and 2 is mounted to reciprocate on suitable ways extendinglongitudinally of the base 16,

grinding and is rovided lwith sides 22 overhanging l i Rotatably jspindle23 the, si e walls of the base.

mounted in the carriage 18 is a4 which carries a grinding wheel 24, andwhich is driven by a belt 25 from an electric motor 26 mounted lon theunderside of the carriage to travel therewith. 'Ihe carriage 18 isarranged to be reciprocated by a piston and cylinder unit, one elementof which is mounted onthe carriage to travel therewith. Preferably thecylinder 27 is rigidly secured to the underside of the carriage 1F, andthe piston 28 is stationarily supported by vhollow rods 29 having theirremote ends mounted in the machine base. These rods communicate with thecylinder 27 at opposite sides of the piston 28 to introduce anddischarge the pressure fluid from and to the main control valve to behereinafter described.

The licaclstoclc carriage vThe headstock carriage 19 (see Figs. 2 and 3)comprises a body section 30 which is slidably mounted on transverse Ways3l on the machine base 16, and a top section 32 which lis rotatablymounted on thebody section and extends therethrough into the base.Journaled in the top section 32 is a rotary work spindle 33 whichcarries a suitable chuck or work fixture 34 on one end for holding theWork to be ground, such as the blank A, and which is driven throughsuitable connections including a movable clutch member 33u and a changespeed gearing 35 by an electric motor 36 mounted together with thegearing on the ,underside of the top section to move and rotatetherewith. The clutch member 33a is provided with Aa yoke 37 pivotallymounted -on a rod 38 and having a depending arm 39.

The gaging mechanism The ga 'ng mechanism (see Figs. 3 to 5) consists oa gage rod 46 extending slidably and axially through the work spindle 33into the chuck 34, and having a pair of gages 47 and 48, designatedrespectively as a roughing gage and a finishing gage, mounted on itsforward end. The roughing gage 47 is smaller `in diameter than thefinishing gage 48, and a little in advance thereof to permit the formerto enter the bore of the blank A before the latter in the course of thegrinding operation. The rear end of the gage rod 46 is connected by abracket 49 to that of a parallel push rod 50 reciprocable in the topsection lou 32 and carrying an abutment roller 51 at its forward end. Acoil spring 52 engaging a collar 53 on the push rod 50 tends to move thegages forward into yielding engagement with the inner edge of the bore1n the blank A, and an adjustable abutment 54 on the rinding spindlecarriage is adapted to stri e the roller 5l to withdraw the gages fromthe work blank A as the grindin wheel 24 advances into the bore of saidlank. When 'the bore has been ground to a predetermined size, theroughing gage only will enter the bore, and when ground to the desiredsize, i. e. when the grinding operation is completed, both gages willenter. The gaging mechanism thus far described is full disclosed in a U.S. Patent No. 1,534,302, issued on April 21, 1925, to PrenticeConradson, Herbert E. Kempton and myself. y

An arm 55 rigidly mounted on the shaft 41 is adapted to engage a block56 loosely mounted on the push rod 50 against the collar 53, and therebyto move the gages into inoperative position away from the work when theclutch member 33a is thrown Ato stop the spindle 33.

. In moving initially past theinner edger` of the work being ground, thegages 47 and 48 cause the successive closing of two switches 57 and 58respectively. Preferably switches of the type disclosed inA a` copendingapplication Serial No. 15,849, filed March 16,1925, by Herbert E.Kempton and myself, now Patent No. 1,751,204, issued March 18, 1930, areemployed.' These switches are housed in a casing 59 secured to the leftend of the body section 32 of the headstock carriage, and comprise twoforked spring contacts 60 and 61 associated respectively with two setsof lixed contacts 62 and 63. The iixed contacts are supported on aninsulating plate 64 over an oil reservoir 65 into which the springcontacts 60 and 61 extend, and two of the ixed contacts, one for eachset, are connected by a conducting plate 66 to which a common lead wireis attached.

The two spring contacts60 and 6l are movably supported by a pair oftripping mechanisms 67 which at the beginning of the grinding operationare locked to hold the contacts open, and which when released will movethe contacts into engagement with the fixed contacts. The trippingmechanisms are adapted to be actuated through two trip dogs 68, one foreach mechanism, which are positioned when said mechanisms are set, to beengaged by apair of plungers 69 slidably extending -into the casing 59.These plungers are adjustably mounted in the bracket 49 for movementwith the gages 47 and 48, and are independently so adjusted that as thegage rod 46 moves in increments suiiciently to the right they will tripthe tw-o mechanisms 67 successively to close the switches 57 and 58 in apredetermined sequence with reference to the progress of the grindingoperation. The switches 57 and 58 after once being closed will beunaffected by the sli ht tem porary withdrawals of the gages rom thework byn the abutment 54. Alpin 70 carried by the push rod 50, whichextends through the casing 59 between the two tripping mechanisms, isadapted to re-set both mechanisms, thereby opening the switches 57 and58 when the clutch member 33a is thrown into open position. l

Feeding mechanism The headstock carriage 19 is arranged to be fed alongthe` ways 31 to move the work blank A against the grinding wheel 24 asthe latter is reciprocated, by means of a feed screw 71 mounted in thevbase 16 and engaging a nut 72 (see Fig. 12) on the underside of the bodysection 30 ofthe carriage. The outer end of the feed screw 71 extendsthrough a feed box 73 (see Figs. 6 and 12) on the front side of themachine, and is provided With a hand wheel 74 whereby it may be manuallyrotated. Within the feed box, a ratchet wheel 75 is mounted on a sleeve76 on the feed screw 71, and is operatively connected through a train ofgears 77 to the screw. The ratchet wheel 75 is adapted to be rotatedintermittently by either one or both of two feed pawls 78 and 79. Thesepawls are pivotally mounted on the oppositely extending arms of two bellcrank levers 80 and 81 respectively, loosely mounted on the sleeve 76,and are resiliently held in engagement with the ratchet wheel 75 bycoiled springs 82. The other arms of the bell crank levers extendhorizontally side by side, and are provided with cams 83 on their lowersides adapted to be engaged by a lever 84 to reciprocate the pawls. Thedegree of oscillation of these arms may be independently adjusted bymeans of two adjustable eccentrics 85 and 86 underlying them andlimiting the downward movement of each of the cams 83. In practice, theeccentrics 85 and 86 are so adjusted that the feed pawl 78, designatedas the coarse feed pawl is given a relatively long reciprocation, andthe pawl 79 designated as the fine feed pawl is given a relatively shortreciprocation.

The lever 84 is adapted to be oscillated by means of a floating piston87 reciprocable in a stationary horizontal cylinder 88. Pressure fluidis successively and alternately re.-

ceived by and discharged from opposite ends of the cylinder 88 throughpipes 89 and 90 connected-with themain control valve.

Mounted in the feed box 73 are two elec.- tromagnates 91 and 92 providedwith armatures 93 and 94 having curved tracks 95 and 96 respectively.The latter underlie rollers 97 and 98 on the pawls 78 and 79, and uponexcitation of the electromagnets will raise the corresponding pawls outof engagement with the ing through the switch 57, wire 101 and theelectromagnet 91, and through the switch 58,

wire 102, and the electromagnet 92 to the wire 103 and the negativeterminal. Since the switches 57 and 58 close in sequence, theelectromagnets will be closed in succession to automatically reduce andfinally discontinue the cross feed as the grinding operation progresses.

To permit manual operation of the feed screw 71 by means of the handwheel 74, the pawls 7 8 and 79 after excitation of the electromagnetsare automatically locked in inoperative position by a pair of latches104 engaging the heels of the armatures 93 and 94. The latches 104 aremounted on a pair of shafts 105 together with releasing levers 106 whichare connected by a suitable linkage 107 and which can be oscillatedsimultaneously by a lever 108 to disengage said latches and therebyrelease said paWls.V

yThe dressing mechanism Mounted on the top section 32 of theheadstockcarriage 19 for movement therewith is a fixed wheel dressingtool (see Figs. 1, 2, 2 and 3). This tool may be supported in anysuitable manner but preferably the mechanism disclosed in my copendingapplication,

iiled May 23, 1924 is employed. That mechanism comprises a base bracket109 which is rigidly bolted to the top section 32 and which is formedwith a pair of parallel spaced arms 110 extending over the bed 16 of thegrinding machine. A cross` member 111 bridges the arms 110, and is adjustable longitudinally thereof. Mounted on the cross member 111 andadapted to be adjusted longitudinally and laterally thereof is anupstanding bracket 112 which is formed on its upper end with a tubularsocket 113. Adjustably mounted in the socket 113y is a tool holder 114(see Fig. 2a) having a bifurcated head 115 in which a mountin 116carrying a diamond 117 is supported or angular adjustment. mond 117 canbe positioned at the proper distance from the outer end of the work, andin proper relation to the surface ofthe Work to be ground. In thepresent instance, the diamond is set at a point which is in substantialalinement with the ground surface of the work but which will at thecompletion of the roughing operation be a trifle nearer the axis ofrotation of the work than said surface.

The operating vmeclzanz'em?.

The hydraulic pressure iiuid, which is preferably oil is drawn from theoil reservoir in the machine base 16 by anoil pump 118 driven by anelectric motor 119, said pump latter to By this construction, the dia-.

' and said motor being mounted on the rear side of the base. Thevoil isdischarged from the pump 118 through a .pipe 120 which communicates withthe inletport, 121 of a main' flowing back to the valve 122 througheither.

of the ports 123 and 124 is returned through outlet ports 127 to the oilreservoir.

The flow of oil through the valve 1.22 is controlled by a reciprocablevalve member 128 adapted to connect the ports 123 and 124 successivelyand alternatel volume of the can be changed to lvary the speed at whichthe carriages 18 and 19 are moved, by changing the Speed of the pump118.

The valve member 128 is provided with-a' stem 129 pivotally connectedwith the lower end of an actuator which is in the form of an uprightlever 130 pivoted between its ends at 131 on the machine base. Movementof the withthe ports' 121 and 127. When the va ve member 128 isv inletport 121 upper end of the lever 130 to the right or left willreciprocate the valve member 128 to cause movement of the spindlecarriage 18 toward or from the chuck mounted in the upper end of thelever 130 and is normally maintained by-a spring follower 133 inoperative position in the path of three dogs 134, 135 and 136 (seeFigs.'1, 8 and 10) which are adjustably secured to the front dependingside 22 of the carriage 18 by bolts 137 engaging in a T-slot 138. and135 are beveled at their left ends to provide cam faces 139 and 140respectively which v upon movement of the carriage 18 from itsinoperative position shown in Figure 1 to the left will successivelyengage and depress the pivotal dog 132 out of the way to permit the snapinto position between the dogs 134 and 135. Upon continuedmovement 'ofthe. carriage 18, the dogs 134- and135 would automatically oscillate thelever 130- to reciprocate the carriage in its operative position. Thedistance through which the carriage will reciprocate depends upon thespacing of the dogs 134 and 135, and is determined by the length of the'bore or surface to be ground, the dogs beingso positioned that thegrinding wheel 24 will reciprocate from one end of the work to theother.

The pivotal vdog 132 is adapted to be automatically tripped when thecoarse feed gage 47 and also past the inner edge of the ground surface.Preferably the' means (see Fig. 7) for ac- 34. A pivotal dog 132 is.

The dogs 136 when the fine feed -gage 4 8 moves Fig. 8)

complishing this comprises an electromagnet 141 mounted in a suitablehousing 142 on the base, and having a pivotal armature 143 to the freeend of which a slidable pin 144 is attached. The pin 144 is arranged toengage the dog 132, and thereby to swin it out of the path of the dogs135 and 136,*liut not far enough to be out of the path of the dog 134. Acatch 145 mounted in the housing 142 is adapted to fall behind the pin144 when the armature 143 is attracted by the magnet coil, to hold thedog in tripped position. or projection 146 which is adapted to ride upona cam face 147 on the dog 135 and also upon two cam faces 148 onopposite'sides of a dog 149 (see Fig. 11) mounted on the left end of thecarriage 18', and which is thereby7 adapted to release the pivotal dog132 after the electromagnet 141 is deenergized.

Excitation of the electromagnet 141 is controlled by a suitable switchmechanism (see which comprises a casing 150 mounted on the front of themachine base. Mounted on insulating sleeve 151 in opposite endsy of thecasing 150 are two fixed contacts 152 and two fixed contacts 153respectively. Two movable contacts 154 and 155 are slidably mounted onthe reduced opposite ends of a reversing plunger 156 reciprocable in thecasing 150, and are adapted to selectively close the contacts 152 and153 with which they constitute switches 157 and 158 respectively. A pairof coiled springs 159 on the plunger 156 tends to press the contacts 154and 155 outwardly against a pair of heads 160 on the extreme ends ofsaid plunger.

The plunger engages and is adapted to be reciprocated bythe downwardlyextending arm of a switch lever at 162 to i the front of the machinebase. Formed on the lower end of the lever 161 is a wedge shapedprojection 163 which engages either side of a pointed spring detent 164mounted in the casing'150 to hold the plunger 156 resiliently in oneextreme position or the other. The lever 161 is formed with an inclinedarm which supports a cam'roller 165 at .its extreme end over the controllever 130 and in the path of the dogs 135 and 149.

When the carriage 18 is in its inoperative position, the plunger 156 ispositioned to the rightthereby closing the switch 157. In the initialmovement of the carriage to operatlve position, the cam roller 165 willengage an upper inclined face 166 on top of the dog 135 which will raisethe roller out of its normal position and thereby move the plunger 156still further to the right relatively to the contacts 152 and againstthe force of the adjacent spring 159. After passing over the dog 135,the rollerunder the influence of the spring 159 will snap back intooperative position, and the switch 157 will still be closed and willremain closed during the roughing The catch 145 is provided with a pin161 pivotally mounted operation. In movement of the carriage 18 towardits inoperative position, when the switch 57 is closed, a sharp cam face167 on the reversing d og 135 will engage and depress the cam roller 165thereby opening the switch 157 and closing the switch 158. Upon a re- Yturn movement of the carriage 18 to operative position, the roller 165will pass under the cam face 166 and the switch 158 will be unaffected.In the final movement of the car riage 18 to inoperative position, thecam roller 165 will ride onto a cai face 168 on the dog 149, and willthereby move the plunger 156 to the right to close the switch 157.

Closure of the switches 57 and 157 completes a circuit through theelectromagnet 141 as follows: from the positive terminal through thewire 100, the switch 57, the wire 101, the switch 157, wire 169, theelectromagnet 141, and wire 170 to the negative terminal, Closure of thevswitches 58 and 158 closes a circuit through the electromagnet 141 asfollows: from the positive terminal, through the wire 100, the switch58, the wire 102, the switch 158, the wire 169, the electromagnet 141,the wire 170,to the negative terminal.

The back-o# `meclumz'imz,

Means (see Figs. 12 to 14) is provided for separating thek grindingwheel 24 and the surface of the work perpendicularly to said surface.This movement is instituted in the present instance just before thegrinding wheel is withdrawn axially from the work. While either ofvthecarriages 18 or 19 may be moved to effect this separation, preferablythe headstock carriage 19 is shifted through the feed screw 71. To thisend, a air of collars 171 are mounted on the fee screw 7l next toashoulder 172, and are separated by a s acer 173. The collars 171 areheldin place y a spacer sleeve'174 positioned between the front collar andthe sleeve 76 in the feed box.- Mounted on the yspacer 173 between thecollars 171 is a yoke 175 having two lateral cylindrical extensions 176which extend pivotall through the arms of a bifurcated head 1 7 on theupper end of a lever 178. The head 177 is pivotally supported on a pin179 in a bracket 180 rigidly secured to the base 16. The bracket 180 isformed integral with a water guard181 which is also secured to the basel16, and which overlaps a shield 182 on the headstock carriage to protectthe parts underneath.

The lower end of the lever 178 is formed with a nob 183 which engages ina milled slot 184 in a reciprocable piston 185. The piston is mounted ina cylinder 186 formed in a casing 187, and closed at its opposite endsby plugs or caps 188 having stops 189 formed thereon. The position ofthe piston is controlled by a valve comprising a cylindrical valvesleeve 190 mounted in the casing 187 and opening at its opposite endsinto an exhaust chamber 191 in the casing.' Pressure fluid from theexhaust 'chamber 191 lis discharged into a pipe 192 leading to .the ko1lreservoir. The sleeve 190 is formed with two sets of end ports 193 and194 communicating with passages 195 and 196'leading tojopposite ends ofthe cylinder 186, anda set of'centra-l ports 197 communicating with aninle l passage 198 connectedy through a pipe 199 to the plpe 120. -Twoplugs 200 are threaded into opposite ends of thecas'lng 187 1n line withthe. sleeve 190.

Reciprocably mounted in the valve sleeve 190 is a valve member 201having two enlargements 2.02 adapted upon reciprocation to successivelyand alternately connect the end ports 193 and 194 with the exhaustchamber 191 and the inlet ports 197. The valve member 201 is providedwith a stem `203 (see Fig. 14) which extends slidably throughone of theend caps 200, and the free end of whlch. 1s pivotally secured to thefree end of the plvotal armature 204 of an electromagnet205.' Theelectromagnet205 is rigidly vsupported on the casing 187, and thecircuit. therethrough isy as follows: from the positive terminal,through .the wire 100, the switch 58, the wire 102, the electromagnet205, and the `1 wire 103 to the negative terminal. A coiled porarywithdrawal from spring 206 on the stem 203, between the armature 204 andthe cap 200 tends to maintain the valve member 201 to the right tomaintain the ports 194 and 197 incommunication. It

vwill be evident that when the gage 48 moves past the inner edge-of thefinished work surface, thereby closing the switch 58, the electromagnet205 will be excited, and will cause the feed screw 71to dinally to theleft to separate the grinding wheel 24 and the finished work surface.

Slow traverse mechanism To obtain a relatively slow traverse of thegrinding wheel 24 in its working reciprocation during the finishingcutand in its movement past the dressing tool 117 on the temthe work, apart of the pressure fluid normally paing through the main control valve122 is, upon entry of the gage 47 into the bore of the work,automatically by-passed to the oil reservoir in the base. To this endthe casing 187 is formed with a cylindrical valve chamber 207 in whichis mounted a valve sleeve 208. The

inlet passage 198 communicates through a plurality of ports 209 with theinterior of the sleeve 208, and the latter is formed in one end with aplurality of port-s 210 opening into an outlet passage 211. Oppositeends of a sleeve 208 open into the exhaust chamber 191. A pair of plugs212 are removably threaded into the ends of the casing 187 in alinementwith the valve sleeve 208.

Reciprocably mounted in the sleeve `208 is a valve member 213 having apair of spaced be shifted longitu- ,enlargements 214 controlling the'yports 209 and 210. The valve member is provided with a stem 215extending through the inner plug 212. The outer end of the stem ispivotally secured to the free end of the armature 216 of anelectromagnet 217 rigidly mounted on the casing. The circuit through theelectromagnet217 is as follows: from the positive terminal through thewire 100, the switch 57, a wire 218, the electromagnet-217 and the wire103 to the negative terminal. A coil spring 219 on the stem 215 betweenthe innerv plu 212 and the armature 216 tends to move t e valve member213 to cut oii' the ports 210 from the ports 209.

The pressure fluid from the outlet passage 211 is passed to the exhaustchamber 191 through a self-adjustable valve which serves y to pass aconstant volume of pressure fluid therethrough irrespective offluctuations in the pressure. These fluctuations may be brought about'by variations in the resistance to the movement of the grinding spindlecarriage 18. For example, at the end of its inward stroke, the carriageassumes the added burden of movin the gages 47 and 48 away from thework. his valve comprisesa cylinder 220 threaded ing 187 and having oneor lmore ports 221 opening into the exhaust chamber 191. A piston 222 isslidably mounted in the cylinfer 220, and is formed with sage 223opening into the outlet passage 211 and communicating through ports 224with lthe ports 221. Movement of the lpiston 222 is controlled andlimited by a der 220. The slot 226 extends along the outside of thecylinder 220 'to the exhaust chamber 191, and permits fluid from thecylinder to be exhausted when the piston 222 moves to the left. A sleeve227 is threaded onto the front end of the cylinder `220 and is closed bya plug is an adJusting nut 229 between which and the inner end of thepiston 222 a coiled spring 230 is positioned to counterbalance thepressure required to move the carriage at a termined speed. The ports221 and 224 normally are in full register to provide the largestpossible openings between the outlet Passage 211 and the exhaustchamber"`191. If the pressure increases, the piston 222 will move theports 221 and 224 partly out of register to reduce the effective area ofthe openings therethrough. If the pressure falls, the piston 222 willmove to the right to enlarge the openings through the ports 221 and 224AThe operation The operation of the machine will be into the wall of thecasa central paspin 225 mountl v ed therein land engaging a slot 226 inthe cylin 228. Threaded into the sleeve 227 predeevident from theforegoing description, and

briefly stated is as follows: 'The work to be ground is placed in thechuck 34, and the lever 42 is actuated to throw the clutch member 33 andstart operation of the spindle 33. By actuating the lever 42, the cam55, releases the push rod 50, thereby permitting the gages 47 and 48 tomove into engagement with the inner end of the work. The lever 130 atthe front of the machine is thrown4 to the right thereby institutingmovement of the grinding spindle carriage 18 to the left to l0 operativeposition. At this stage of the machine operation, the switch 157 isclosed.

As the grinding spindle carriage moves toward its operative position,the dogs 13G and 135 will successively depress the pivotal dog 132 topermit the latter to snap into position between the dogs 134 and 135 toinstitute and effect an automat-ic reciprocation of the grinding wheelin its operative position. At the inner end of each stroke of thereciproca- 20 tion, the abutment 54 will withdraw and hold the gages 47and 48 away from the work. Meanwhile the work is moved into engagementwith the grinding wheel 24 by turning the hand wheel 74, and theautomatic cross feed is then instituted by actuating the lever 108 torelease the feed pawls 78 and 79.

The grinding wheel 24 continues' to reciprocate in the work, and the.headstock carriage to be fed transverselyJof the grinding wheel untilthe work is ground to a predetermined size, whereupon the foremost gagewill move past the inner edge of the surface being ground. Thedressinglr tool 117 is plositioned substantially in line with but atrifle nearer the axis of rotation than the resulting surface of thework.

Movement of the gage 47 past the inner' edge of the work results in theclosure of the switch 57 which closes the circuits through theelectromagnets 91, 141 and 217. The electromagnet 91 raises the pawl 78,and effects a reduction in the rate of the cross feed. The electromagnet141 trips the pivotal dog 132 and prevents a reversal of the lever 130by the dog 135, thereby causing the grinding wheel to be withdrawnaxially from the y bore of the work. The electromagnet 217 moves thevalve member 213 to the left, thereby by-passing a portion of thepressure Huid normally directed to the main valve 122, and consequentlyeffecting a reduction -in the speed of traverse of the grinding wheel24. In the withdrawal movement of the carriage, the roller 165 of thelever 161 is depressed 55 b the cam face 167 thereby opening the switch157 and closing the switch 158. This results in a deenergization of theelect-romagnet 141. The pin 146 engages the cam surface 147 thereuponreleasing the pivotal dog 132 which is positioned between the dogs 135and 136.y The carriage 18 continues its movement toward inoperativeposition until the dog 130 reverses the lever 130, and causes a returnof the carriage to its operative position.

In the temporary withdrawal of the grinding wheel from the work, thegrinding wheel 24 is moved past the ixedwheel dressing tool 117 whichtrues its surface. Since a portion of the pressure'luid is by-passedthrough the casing 187, this movement of the grinding wheel 24 past thedressing tool 117 will be relatively slow to permit the wheel to vbeaccurate y dressed.

In the return of the carriage to its operative position, the pivotal dog132 is again depressed by the dog 135, and snaps into position betweenthedogs 134 and 135. Reciprocation of the carriage continues at the slowspeed until the gage 48 moves past the inner edgel of the surface,whereupon the switch 58 is closed thereby resulting in the excitation ofthe electromagnets 92, 141 and 205. Excitation of the electromagnet 92raises the feed pawl 79 and stops the cross feed. Excitation of theelectromagnet 141 again trips the pivotal dog 132 and permits/awithdrawal of the grinding wheel from the bore of the work. In thisinstance the position of the lever 161 is unaffected by the do 135, andthe switch 158 remains closed there y causing the electromagnet 141 toremain energized and permitting the carriage to move to its inoperativeposition. Just before the carriage 18 reaches its inoperative position,the lever 161 is oscillated by the cam face 168 thereby opening theswitch 158 and closing the switch 157. The electromagnet 141 is thendeenergized, and the pivotal dog 132 is released by the cam surface 148.Simultaneously with the beginning of the withdrawal movement, excitationof the electromagnet 205 causes the piston 185 to oscillate the lever178 and shift the headstoc-k carriage 19 along the ways 31 therebyeffecting a separation of the grinding wheel 24 and the finished surfaceof the work before the withdrawal of the grinding wheel beyond the endof the work. This lnovement causes the grinding wheel to he withdrawntoward its inoperative position without engaging the finished surface ofthe work or the dressing tool. After withdrawal of the grinding wheel 24from the work and past the dressing tool 117, the clutch lever 42 isoperated to stop the spindle 33, thereby moving the gage rod to the leftto open the switches 57 and 58. This results in a deenergization of allthe electromagnets. As a result the headstock carriage 19 is rcturned toits initial position', and the carriage 18 completes its movement toinoperative position at high speed.

By applying a fixed wheel truing device to the headstock carriage formovement therewith, and by effecting a lateral separation between thegrinding wheel and the work before a separation of the grinding wheeland the work axially of the former, contact between the grinding wheeland the surface is avoided on the final withdrawal movement,

and dressing ofthe grinding ywheel is pereral machine operation.

I claim as my invention: 1. A grinding machine having, in combimatic,and results incidentally from tie gennation, a headstock for supportingthe work, lmeans supporting a grinding wheel, control means governed bythe progress of the grinding operation, operating means under thecontrol of said-control means .for moving the work and said grindingwheel relatively to each other to bring said grinding wheel from aninoperative position remote from said work into operative position, toreciprocate said grinding wheel across the work in said operativeposition, to effect a temporary axial separation of the work and saidgrinding wheel at an intermediate stage in the grinding operation, and afinal axial se aration therebetween .at the completion o said grindingoperation, a truing device mount- L ed, in fixed relation to saidheadstock and 'having a dressing tool positioned to engage and dresssaid grinding wheel upon said temporary separation, and means under thecontrolof said control means for effecting a lateral separation of theground work surface and said grinding wheel when the grinding operationhas been completed to cause said grinding wheel to clear said surfaceand said dressing tool on said final separation.

2. A grinding machine having, in combination, means for supporting thework, a

grinding wheel and support therefor, control means governed by theprogress of the grinding operation, means for effecting a relativereciprocation between the work and said grinding wheel, said means beingcontrolled by said control means to automatically efi'ect an axialseparation lof the work and said grinding wheel 'first temporarily at a.predetermined intermediate stage of the grinding operation and finallyat the completion of the grinding'operation, and being operable toautomatically return said grinding wheel to the work after said firstseparation, a dressing tool fixed in substantial alinement with the worksurface and hence adapted to engage said grinding wheel as the latter ismoved past said tool in said temporary separation, and means /under thecontrol of said control means operable at the `completion of thegrinding operation to automatically separate the finished work surfaceand said grinding wheel laterally of said grinding wheel beforesaidfinal axial separation.

3. A grinding machine having, in combination, a headstock for supportingthe work, a carriage having a grinding wheel, means for moving saidcarriage to move said grinding wheel from inoperative position remotefrom thework into operative position, re-

vseparating movement, and means for automatically separating said'inding wheel and the finished surface of t e work at the completion ofthe grinding operation to cause said grinding wheel to clear saidsurface and said dressing tool on the final withdrawal movement.

4. A grinding machine having, in combination, a headstock for supportingthe work, a carriage having a grinding wheel, control means governed bythe progress, of the grinding operation, means for moving said carriagerelatively to said headstock to reciprocate said grinding wheel acrossthe surface of said work to separate said grinding wheel from the workat a predetermined stage in the grinding operation, to return saidgrinding Wheel to the work and continue said reciprocation, and to againseparate said grinding wheel from the work at the completion of thegrinding operation, a dressing tool mounted in fixed `relation to theheadstock and positioned to engage said grinding wheel as it iswithdrawn from the work in the first separation, and means under thecontrol of said control means automatically operable at the completionof the grinding operation to effect a separation ofthe finished surfaceof the work and said grinding wheel tocause said grinding wheel on itsfinal withdrawal to clear said surface and said dressing tool.

5. A grinding machine having, in combination. a headstock forVsupporting the work, a grindingwheel and support therefor, means formoving said headstock and said grinding wheel relative .to each other toreciprocate. said grinding wheel across the surface of the work andeffect an axial separation therebetween at a predetermined stage in thegrinding operation and also at the completion of the grinding operation,l mounted in fixed relation to the headstock and positioned'toengagat-he grindingwheel upon said first separation, and means autoadressing` tool v matically operable upon the completion of the i' in thegrin ing operation, a dressin tool mounted in fixed relation to the heatock and positioned to engage said grinding wheel A as the latter isseparated from the work, and means automatically operable subsequent tosaid separation to separate the finished surface of the work and saidrinding wheel to permit withdrawal of sai grinding wheel from the workwithout contacting with said dressing tool.y

7. A grinding machine having, in combination, a headstock for supportingthe work, a carriage having a grinding wheel adapted to engage the work,control means governed by the progress of the grinding operation,0perating means under the control of, said control means for separatingthe work and said grinding wheel axially at a predetermined stage in thegrinding operation and returning saidgrinding wheel to the work, andagain separating the work and said grinding wheel at the completion ofthe grinding operation, a dressing means mounted in fixed relation tothe headstock and positioned to engage said grinding wheel in said firstseparation, and means under the control of said control means forautomatically shifting said headstock upon completion of the grindingoperation to separate the finished surface of the work andsaid grindingwheel laterally before the final withdrawal of said grinding wheel fromthe work past said dressing means.

8. A grinding machine having, inl combination, a headstock forsupporting the work, a grinding wheel and a supportftherefor, controlmeans governed by the progress of the grinding operation, means underthe control of said control means for effecting a relative graduatedcross feed between the work and said grinding wheel, said cross feedbein automatically reduced at the completion o the roughing operationand being automatically discontinued at the completion of the entireoperation, operating means under `the and means under the control ofsaid control means automatically operable upon completion of thegrinding operation to separate the finished work surface and saidgrmding wheel laterally of said wheel before completion of the finalwithdrawal of the latter so that said grinding wheel will clear theground surface and said dressing tool in said final withdrawal. l

9. A grinding machine having, in combination, a headstock for supportingthe work, a grinding wheel and a support therefor,

means for moving said headstock and said grinding wheel relative to eachother to reciprocate said grinding wheel across the surface of the workand to effect an axial-separation therebetween at a predetermined stagein the grinding operation and also at the com pletion of the grindingoperation, a dress.- ing tool mounted in fixed relation to saidheadstock and positioned to engage said grinding wheel upon said irstseparation, means automatically operable upon the completion of thegrinding operation to se arate the finished surface of the work an saidgrinding Wheel soas to cause said grindingwheel to clear said surfaceand said dressing tool on said final separating movement, and meansautomatically operable at said predetermined stage to slow down thespeed of relative axial, movement between said grinding wheel and thework so as to cause said grmding wheel to move slowl past said dressingtool in the course of said first separation.

10. A inding machine having, in combination, a eadstock for supportingthe work, a grinding wheel and support therefor, control means governedby the progress of the grinding operation, operating means under thecontrol of said control means for withdrawing said grinding wheel be ondthe end of said work at a predetermine stage in the grinding operation,a dressing tool mounted in fixed relation to the headstock andpositioned in' substantial alinement with the ground surface of the workat the time of said withdrawal, and means under the control of saidcontrol means for separating the finished work surface and said grindingv wheel at the completion of the grinding opwithdrawn beyond the end ofthe work and past said dressing tool without contacting therewith.

11. A grinding machine having, in com- .eration to permit said grindingwheel to be bination, a headstock for supporting the work, meanssupporting a grinding wheel, a truing device mounted on said headstoekand positioned in alinement with a preliminary work surface to beground, control means governed by the progress of the grindingoperation, operating -means operable to automatically institute aworking reciprocation between the work and said grinding wheel inmovement of said grinding wheel relatively to the work from a remoteinoperative position into operative, position, and operable toautomatically reciprocate the work and said grinding wheel relativel toeach other in said o erative position, said control means control ingsaid operating means to temporarily extend the working stroke of saidreciprocation when said preliminary surface has been ground so as tomove said v grinding wheel across said truing device, and

again to extend the Workinglstrokeat the completion of the grindingoperation so as to efect a nal axial separation of the work and said'grinding wheel, and means under the control of said ,control means foreffecting a separation of the inished Work surface and said grindingwheel laterally of p said wheel when the grinding operation has beencompleted to cause said grinding wheel to clear said finished surfaceand said truing device in said final separation.

` 12. A grinding machine having, in comf bination, a headstock forsupporting the `work, means supporting a grinding wheel,`

a truing tool mounted on said headstock and .positioned in substantialalinement with the surface to be ground, means for automaticallyreciprocating the grinding wheel relative-A ly across the work surfaceand said truing tool, and means automatically operable at the completionof the grinding operation to effect a lateral separation of the finishedwork surface and said grinding wheel to cause said grinding wheel toclear said finished surface and said truing tool on furtherreciprocatory movement.

In testimony whereof I have hereunto affixed my signature. KEITH F.GALLIMORE.

